1. Field of the Invention
The present invention relates in general to highway construction equipment, and in particular to an attachment for a backhoe or other earthmoving machine for shaping a trench and/or plowing a base or paving material to a uniform depth.
2. Description of the Prior Developments
Various attachments have been available for forming trenches and ditches in connection with the construction and maintenance of roads and highways. Although these attachments perform satisfactorily in general, they are not particularly well suited for maintaining a uniform trench depth and width. Moreover, such attachments typically do not control the lateral movement of earth and other material as a ditch is being formed, and such attachments do not have the capability of accurately spreading a level layer of material within or above the surrounding road surface while maintaining clean sides for subsequent compaction by a roller.
Accordingly, a need exists for a trench forming apparatus which is of a relatively simple design, yet which can accurately maintain the relative depth of a trench within close limits.
A further need exists for such an apparatus which can direct plowed earth and material laterally inwardly toward a trench or laterally outwardly away from the trench as the height of the ditch is being plowed and conditioned.
Still a further need exists for such a trenching apparatus which has a vertically adjustable blade for accurately adjusting the height of a trench.
Yet a further need exists for a trench or road working apparatus which can level a trench at a height below the surrounding road surface, as well as spread material such as blacktop at a level above the surrounding road surface.
The present invention has been developed to fulfill the needs noted above and therefore has as an object the provision of a trench leveling and conditioning apparatus having a generally simple design yet which can accurately maintain the depth of a trench within close limits.
A further object of the invention is the provision of a trench conditioning apparatus which can be easily attached to a power machine such as a backhoe or wheel loader and which can control the placement of material moved along the trench.
Yet a further object of the invention is the provision of a trench conditioning apparatus having a central height-adjustable blade for setting a trench depth and a pair of adjustable side blades for controlling placement of earth and material located along the sides of a trench and for keeping the earth and material away from the wheels and skids of the apparatus.
A further object of the invention is to provide a trench and road conditioning apparatus which has a height adjustable blade for forming a level trench surface below the surrounding road surface, or spreading a level layer of road material at a height above the surrounding road surface.
These and other objects are met by the present invention which is directed to a trench conditioning apparatus having a pair of slotted side walls adapted to receive the bucket of a power machine such as a backhoe or wheel loader. A vertically adjustable central blade is supported between the side walls, and a pair of pivoting adjustable side blades is mounted to the side walls on opposite sides of the central blade.
The side blades can be pivoted in front of the central blade to laterally direct and plow earth and material into the path of the central blade, or pivoted in back of the central blade to laterally direct and plow earth and material away from the trench and the central blade. In either case, the side blades keep the existing paved edges of the road surface adjacent the trench clean and free of earth and material and thereby provide a clean surface over which the casters and skids of the apparatus and the wheels of the machine used to push it can move. This helps to keep the central blade level insofar as material passing under the wheels of the apparatus and machine used to push the apparatus tends to lift the central blade out of level alignment with the trench.
The invention can be used with trenches in virtually any condition, but is particularly adapted for use in trenches which have already been backfilled and compacted. When the trenching apparatus is then moved along such a preconditioned trench, an extremely smooth trench having an accurately selected height can be produced.
If desired, the central blade can be raised higher than the side blades and higher than the adjacent pavement over which the side blades ride. In this raised blade position, the trenching apparatus can be used to spread materials such as aggregates and/or blacktop at any desired height, even a height higher than the existing road to allow for subsequent height compaction when the aggregates and/or blacktop are rolled and compressed by a steamroller or other compaction machine. The range of height is from 14xe2x80x3 below the road to 3xe2x80x3 above the road.
The aforementioned objects, features and advantages of the invention will, in part, be pointed out with particularity, and will, in part, become obvious from the following more detailed description of the invention, taken in conjunction with the accompanying drawings, which form an integral part thereof.